AlwaysOn Availability Groups configuration - easy steps to follow

AlwaysOn Availability Groups, introduced in SQL Server 2012, is the latest feature from Microsoft for providing high-availability and disaster recovery solutions.

The feature is available only for Enterprise edition of SQL Server 2012 and SQL Server 2014 and combines Windows failover clustering with SQL Server database mirroring.

Regarding the number of nodes in AlwaysOn Availability Groups, SQL Server 2012 supports a maximum of four secondary replicas and SQL Server 2014 supports a maximum of eight secondary replicas.

I won't enter into details regarding the definition or the configuration of AlwaysOn Availability Groups, instead I will point the steps to follow and to consider when configuring it.

Step 1. Configure Windows Server Cluster (a feature of Windows Server operating system).

Step 2. Install SQL Server Database Engine (2012/2014 enterprise edition) on each node:

• Installation as New SQL Server stand-alone installation (not in failover cluster mode);
• SQL Server service accounts configured to Windows domain users;
• All instances should have the same name;
• All instances should have the same collation;
• Make sure each instance has the same path for user databases (data files and log files). Not the same disks for storage, but the same configuration and path.

Step 3. Choose a shared location for backups and give permissions on it to all SQL Server database engine service accounts.

All instances configured in AlwaysOn need to have access to databases backups.

Step 4. Make sure each SQL Server service account has permissions on all related datafiles and logfiles folders.

Step 5. Configure static port on each instance and restart the services (if it's not the default instance).

Step 6. Open inbound rules for the static ports in Windows Firewall.

Step 7. Enable AlwaysOn on each instance in Configuration Manager and restart the services.

Step 8. Go to primary replica (the node you choose as active/primary) and prepare the database:

• Set recovery model to FULL;
• Backup full the database to the shared backup location (on which all service accounts have permission).

Step 9. Run New Availability Group Wizard on the primary replica:

• The wizard creates endpoints for each instance;
• Add inbound rules in Windows Firewall for the endpoints ports on each server;
• Choose the databases you want to add to Availability Groups.

Step 10. Add a Listener to the Availability Group and configure it:

• Assign an unique name within Active Directory;
• Assign a new, unused IP in the chosen subnet;
• Assign an available port (the default port is TCP 1433, but if it is used by MSSQL or another application, assign another);
• Add inbound rule in Windows Firewall for the Listener port on all servers.

And this is all.

Other settings like Initial Role, Automatic Failover, Readable Secondary etc.  can be done during the initial configuration and after, but taking in consideration the steps above will make it work.